1. Field of the Invention
This invention relates to surgically implantable sleeves for implanting inside of blood vessels, and more particularly relates to such a sleeve that is collapsible such that it can be implanted in the aorta or other artery through an incision or percutaneous puncture into the lumen of the femoral artery.
1. Prior Art
This invention was set out and described in an earlier U.S. patent application, Ser. No. 07/201,191, now abandoned.
Stable and asymptomatic abdominal aortic aneurysms are quite common. The standard treatment for asymptomatic abdominal aortic aneurysms is to surgically remove the aneurysm and graft a replacement prosthetic section into the aorta. However, such surgery is generally postponed until the aneurysm has grown to a diameter greater than five cm. With aneurysms over five cm in diameter, the risk of complications is greater than the risks inherent in surgical excision and grafting of the aneurysm. Consequently, symptomatic aortic aneurysms, or those that show a rapid increase in size, or those greater than five cm in diameter are generally surgically removed and grafted as a matter of course, before rupture occurs.
The standard surgical procedure for repairing an abdominal aneurysm includes one or two days of preparing the large and small intestines prior to hospitalization. The actual operation generally takes one to three hours, and may necessitate four or more units of blood transfusion. The patient commonly remains hospitalized for seven to ten days following surgery, and usually requires as much as three months recuperation time before returning to work.
Even for this elective surgical excision and grafting of an abdominal aortic aneurysm, there remains significantly high rates of mortality and morbidity. The mortality rate is as high as five percent (5%). The morbidity rate includes incident complications such as blood loss, respiratory tract infections, wound infections, graft infections, renal failure, and ischemia of the bleeding intestine. The mortality and morbidity rates for this type of major surgery are also often influenced by the fact that the typical aortic aneurysm patient is elderly and therefore less able to withstand major surgery and a major anesthetic.
The common surgical procedure for repairing an abdominal aortic aneurysm is to excise part or all of the aneurysm and replace the aneurysmal aortic section with a man made tubular section, sutured end-to-end to the severed aorta at a site proximal to the origination of the aneurysm. Other types of replacement sections have flat metal rings or tube sections in each end. These metal rings or tube sections are placed inside the exposed aorta ends, and retained in place by either securing ligatures around the exposed ends to compress the aorta against the metal tube sections, or by clamping the exposed aorta ends against the tube sections with a metal or other suitable clamp.
Other non-aneurysmal medical treatments have involved positioning various devices in place via a catheter into the vascular system. The intra-aortic balloon pump is almost always placed in position via the femoral artery. Such an arrangement is shown in a Kreamer U.S. Pat. No. 4,577,631. The balloon pump is only a temporary device, however, and must be surgically removed within days or weeks.
A device known as a Mobin-Uddin umbrella is a stainless steel and silicone rubber device that is used to trap thromboembolic traveling along the inferior vena cava towards the heart and lungs. This device is generally placed in position within the inferior vena cava via the internal jugular vein, or via the femoral vein.
Similarly, a filter known as a stainless steel Greenfield filter can be placed in position with a catheter into the inferior vena cava, via the femoral vein or the internal jugular vein.
Further, several conduit prosthesis for implantation as a surgical treatment for dissecting an aortic aneurysm are shown in Whalen U.S. Pat. No. 4,130,904 and Koyamada U.S. Pat. No. 4,313,231. Also, grafts, similar to the present invention in that they are characterized as being movable from a collapsed formation of a diameter less than the diameter of a vessel to an open formation of a diameter approximately equal to that of a vessel, are shown in Choudhury U.S. Pat. No. 4,140,126 and to Kornberg, No. 4,562,596, none of which collapsible grafts alone or in a reasonable combination, however, anticipate the present invention, as set out and claimed herein.
As set out above, it is well known to place devices within the vascular system via catheters. Conventional tubular aortic replacement sections, however, are generally considerably larger in diameter than the femoral artery and therefore cannot be inserted through the femoral artery lumen. Also, where such devices have been proposed, for example the devices of the Choudhury and Kornberg patents, the expanding structure thereof appears to be cumbersome, difficult to operate, is generally unreliable and is structurally different from the present invention. Additionally, even if it were possible to position such a tubular aortic section within the aortic aneurysm, prior to the tacking device set out herein, it was essentially impossible, without major surgery, to secure ligatures or other clamps around the aorta to compress so as to secure the aorta against the tubular aortic section.